Data storage apparatus that appropriately revises FDCB information during background formatting

ABSTRACT

A data storage apparatus, including a controller that formats a rewritable recording medium in the background, interrupts the background formatting when a host computer requests to store data in the rewritable recording medium, stores the data in the rewritable recording medium after interrupting the background formatting, revises control information stored in a predetermined region of the rewritable recording medium after storing the data, and resumes the background formatting after revising the control information. The data storage apparatus according can revise control information indicating the address up to which the background formatting has been performed and the address of an unformatted recording region in which user data have been recorded, for example, at an appropriate timing during the background formatting.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention generally relates to a data storage apparatus, andmore particularly, to a rewritable data storage apparatus such as aCD-RW disk drive and a DVD+RW disk drive that can interrupt backgroundformatting when data storage is requested.

2. Description of the Related Art

Universal Disk Format (UDF) is known as the standard file format forrewritable data storage media. Since CD-RW and DVD+RW are furthercapable of overwriting in addition to being writable, they employ RandomUDF that enables a disk drive to store and retrieve data randomly. Inthe case of CD-RW disks, a user is required to format the recordingregion of a CD-RW disk, entirely or partially, by recording dummy databefore storing data.

In the case of DVD+RW disks, the user is still required to format aDVD+RW disk by recording dummy data in a recording region if the userwishes the DVD+RW disk to be retrievable (readable) by a conventionalDVD-ROM drive.

Accordingly, the formatting of a disk takes time since the recordingregion of the disk needs to be filled with dummy data. The more storagecapacity the disk has, the more time is required to format the disk. Theuser cannot store data until the formatting of the disk is completed.

A conventional solution to the above problem is background formattingwherein an optical disk drive formats a portion of an optical-disk sothat it can store data in or retrieve data from the optical disk even ifthe optical disk is not fully formatted. Japanese Patent Laid-openApplication No. 11-134799 discloses a data storage apparatus such as aCD-RW disk drive and a DVD+RW disk drive that formats an optical disk inthe background so that it can store data in the optical disk within ashort time after the background formatting is requested. In thebackground formatting, the data storage apparatus stores dummy data inany unrecorded (unformatted) region of the optical disk while no requestfrom the host computer for data storage or retrieval is being processed.If the host computer requests for data storage or data retrieval duringthe background formatting, the optical disk drive interrupts thebackground formatting and stores (retrieves) data in (from) the opticaldisk.

Accordingly, the data storage apparatus' performs the backgroundformatting and the data storage (retrieval) requested by the hostcomputer in parallel (concurrently). That is, even if the backgroundformatting is proceeding, the data storage apparatus can store(retrieve) data in (from) any region of the optical disk. The user caneject the optical disk while the background formatting is proceeding.

It is necessary to record which portion of the optical disk has beenformatted and in which portion of the optical disk data have been storedso that the optical disk drive can randomly store data in any region ofthe optical disk or eject the optical disk while the optical disk isbeing formatted in the background.

In the case of a DVD+RW disk, the above information is recorded in aregion called a Formatting Disk Control Block (FDCB) in the lead-inregion of the disk.

FDCB includes recording state information indicating whether the disk isnot formatted, is being formatted, or has been formatted, addressinformation indicating the address of the formatted region of the disk,and bit map information indicating whether a region is recorded orunrecorded.

When a partially formatted optical disk is inserted, the optical diskdrive can resume background formatting and store dummy data only in theunrecorded region by referring to the FDCB.

FDCB is so important, especially in the case wherein the optical disk isejected during the background formatting, that the optical disk drivecorrupts user data if the information stored in FDCB is incorrect, byoverwriting dummy data on the user data.

On the other hand, if FDCB is rewritten too often, the performance ofthe optical disk drive is lowered and the degrading of the optical diskis accelerated.

SUMMARY OF THE INVENTION

Accordingly, it is a general object of the present invention to providea novel and useful data storage apparatus in which one or more of theproblems described above are eliminated.

Another and more specific object of the present invention is to providea data storage apparatus that can appropriately rewrite new informationin connection with formatting and a recording previously stored in arecording medium

To achieve the above objects, a data storage apparatus according to thepresent invention includes a controller that formats a rewritablerecording medium in the background, interrupts the background formattingwhen a host computer requests to store data in said rewritable recordingmedium, stores said data in said rewritable recording medium afterinterrupting the background formatting, revises control informationstored in a predetermined region of said rewritable recording mediumafter storing said data, and resumes the background formatting afterrevising said control information.

The data storage apparatus according to an embodiment of the presentinvention can revise control information indicating the address up towhich the background formatting has been performed and the address of anunformatted recording region in which user data has been recorded, forexample, at an appropriate timing during the background formatting.

Other objects, features, and advantages of the present invention willbecome more apparent from the following detailed description when readin conjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a block diagram showing an optical disk drive according to anembodiment of the present invention;

FIGS. 2A-2D are schematic drawings showing how the background formattingand the user data storage are performed according to an embodiment;

FIG. 3 is a flow chart showing background formatting of the optical diskdrive showed in FIG. 1 according to the first embodiment of the presentinvention;

FIG. 4 is a flow chart showing background formatting of the optical diskdrive showed in FIG. 1 according to the second embodiment of the presentinvention;

FIG. 5 is a flow chart showing background formatting of the optical diskdrive showed in FIG. 1 according to the third embodiment of the presentinvention;

FIG. 6 is a flow chart showing background formatting of the optical diskdrive showed in FIG. 1 according to the fourth embodiment of the presentinvention;

FIG. 7 is a flow chart showing background formatting of the optical diskdrive showed in FIG. 1 according to the fifth embodiment of the presentinvention;

FIG. 8 is a flow chart showing background formatting of the optical diskdrive showed in FIG. 1 according to the sixth embodiment of the presentinvention;

FIG. 9 is a flow chart showing background formatting of the optical diskdrive showed in FIG. 1 according to the seventh embodiment of thepresent invention; and

FIG. 10 is a schematic drawing showing an information processing systemhaving a data storage apparatus according to another embodiment of thepresent invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The preferred embodiments of the present invention will be described indetail below by reference to the drawings.

FIG. 1 is a block diagram showing an optical disk drive according to anembodiment of the present invention.

The optical disk drive includes spindle motor 1 that rotates opticaldisk 11, which is a rewritable optical disk such as CD-RW and DVD+RW,optical pickup 2 that has an embedded semiconductor laser therein andapplies laser beam L to a recording region of optical disk 11, andcoarse motor 3 that actuates optical pickup 2 in the radial direction ofoptical disk 11 in collaboration with a seek motor (not showed) embeddedin optical pickup 2.

The optical disk drive further includes rotation control unit 4 thatcontrols the rotation of spindle motor 1, coarse motor control unit 5that controls the actuation of coarse motor 3, pickup control unit 6that controls optical pickup 2, and signal processing unit 7 thatprocesses a signal reproduced from optical disk 11 and a signal beingrecorded in optical disk 11 by optical pickup 2.

The optical disk drive further includes cache memory 8 that temporarilystores data retrieved from optical disk 11, and main control unit 9 thatconsists of CPU, ROM, and RAM, for example, and performs variousfunctions according to an embodiment of the present invention incollaboration with the above units 4-7.

Main control unit 9 is connected to a host computer through externalinterface 10. In response to a request from the host computer, maincontrol unit 9 transmits data retrieved from optical disk 11 to the hostcomputer, and receives from the host computer data to be stored inoptical disk 11.

The optical disk drive rotates optical disk 11 by spindle motor 1,actuates optical pickup 2 in the radial direction of optical disk 11,and applies laser beam L emitted by a semiconductor laser embedded inoptical pickup 2 to a recording region of optical, disk 11 so that theoptical disk drive performs background formatting and user data storagein parallel according to the present invention.

In the case of recording, the optical disk drive receives data from thehost computer through external interface 10. The data are temporarilystored in cache memory 8, and converted into a recording signal bysignal processing unit 7. Optical pickup 2 applies laser beam L on therecording region of optical disk 11 in response to the recording signal.

In the case of retrieval, the optical disk drive retrieves data fromoptical disk 11 in response to a request for data retrieval of the hostcomputer. The retrieved data are temporarily stored in cache memory 8,and transferred to the host computer through external interface 10.

FIGS. 2A-2D are schematic diagrams showing how data are stored in arecording medium such as a DVD+RW disk by background formatting and datastorage in response to a user's request.

The recording medium has lead-in region 21, user data region 22, andlead-out region 23. When a blank (unformatted) disk is set in theoptical disk drive (hereinafter referred to as drive), the driveinitializes a portion 24 of lead-in region 21 in the foreground to forma region 25 called FDCB in region 24. The drive records “data storagestatus information” in FDCB 25. The drive is now ready to accept arequest of the host computer for data storage (FIG. 2A).

The drive starts formatting user data region 22 from the inner radius tothe outer radius of the disk by storing dummy data therein in thebackground (FIG. 2B).

When the host computer requests for data storage or retrieval, the driveinterrupts the background formatting, and stores user data 27 in orretrieves user data 27 from user data region 22 (FIG. 2C)

After completing the data storage and retrieval requested by the hostcomputer, the drive resumes the background formatting starting from theaddress at which the drive interrupted the background formatting. Thatis, the drive formats region 28 and 29 where data have not yet beenrecorded.

If the drive is required to eject the disk during the backgroundformatting, the drive stores the data storage status information in FDCB25 in lead-in region 21 before ejecting the disk (FIG. 2D). The datastorage status information contains an address P1 at which thebackground formatting is interrupted and the information indicating inwhich region of the unformatted region the user data are recorded.

Various embodiments of the present invention will be described below byreference to FIGS. 3-9.

FIG. 3 is a flow chart showing background formatting of the optical diskdrive showed in FIG. 1 according to the first embodiment of the presentinvention. Main control unit 9 starts formatting the disk in thebackground. Main control unit 9 checks whether the background formattinghas been completed (step S1). If the background formatting has not beencompleted, main control unit 9 further checks whether the host computerrequests for data storage (step S2) If the host computer does notrequest for data storage, main control unit 9 returns to step S1. If thehost computer requests for data storage, main control unit 9 interruptsthe background formatting (step S3) and stores data as requested by thehost computer (step S4).

Main control unit 9 stores data storage status information in FormattingDisk Control Block (FDCB) 25 of optical disk 11 (step S5). Main controlunit 9 resumes the background formatting (step S6) and returns to stepS1 followed by the above process. If the background formatting has beencompleted in step S1, main control unit 9 exits this process.

The optical disk drive according to this embodiment stores the datastorage status information in FDCB 25 as soon as the optical disk drivecompletes data storage as requested by the host computer. Accordingly,if optical disk 11 is temporary ejected and set in the optical diskdrive again, the optical disk drive can determine the data storagestatus information by retrieving it from FDCB 25 of optical disk 11.

In the case wherein the host computer makes a plurality of successiverequests for data storage during the background formatting, it is notnecessary to store data storage status information in FDCB 25 each timethe host computer makes such requests. If FDCB 25 is revised too often,the performance of the optical disk drive is lowered and the degradingof the optical disk is accelerated.

Modifying the process as described below by reference to FIG. 4 may bebeneficial to solve the above problem.

FIG. 4 is a flow chart showing background formatting of the optical diskdrive showed in FIG. 1 according to the second embodiment of the presentinvention.

Main control unit 9 starts formatting the disk in the background. Maincontrol unit 9 checks whether the background formatting has beencompleted (step S11). If the background formatting has not beencompleted, main control unit 9 further checks whether the host computerrequests for data storage (step S12). If the host computer does notrequest for data storage, main control unit 9 returns to step S11. Ifthe host computer requests for data storage, main control unit 9 checkswhether the background formatting is proceeding (step S13). If thebackground formatting is proceeding, main control unit 9 interrupts thebackground formatting (step S14) and stores data as requested by thehost computer (step S15)

In response to the completion of the data storage requested by the hostcomputer, main control unit 9 starts measuring time (elapsed time) up toa predetermined time before resuming the background formatting.

Main control unit 9 checks whether the predetermined time has passed(step S16). If the predetermined time has not passed, main control unit9 returns to step S11 and repeats the process between steps S11 and S13.If the host computer requests for data storage in step S12 and thebackground formatting is not proceeding in step S13, main control unit 9goes to step S15 and stores the data as requested by the host computer.Main control unit 9 checks whether the predetermined time has passed(step S16). If the predetermined time has passed, main control unit 9stores data storage status information in Formatting Disk Control Block(FDCB) 25 of optical disk 11 (step S17). Main control unit 9 resumes thebackground formatting (step S18) and returns to step S11 followed by theabove process. If the background formatting has been completed in stepS11, main control unit 9 exits this process.

In the case wherein the host computer makes a plurality of successiverequests for data storage during the background formatting, the opticaldisk drive according to this embodiment revises FDCB 25 after all dataare stored. Accordingly, the performance of the optical disk drive issustained at a high level and the optical disk is not degraded sinceFDCB 25 is not revised (written to) too often.

FIG. 5 is a flow chart showing background formatting of the optical diskdrive showed in FIG. 1 according to the third embodiment of the presentinvention.

Main control unit 9 starts formatting the disk in the background. Maincontrol unit 9 checks whether the background formatting has beencompleted (step S21). If the background formatting has not beencompleted, main control unit 9 further checks whether the host computerrequests for data storage (step S22). If the host computer does notrequest for data storage, main control unit 9 returns to step S21. Ifthe host computer requests for data storage, main control unit 9 checkswhether the background formatting is proceeding (step S23).

If the background formatting is proceeding, main control unit 9interrupts the background formatting (step S24) and stores data asrequested by the host computer (step S25).

In response to the completion of the data storage requested by the hostcomputer, main control unit 9 starts measuring time up to a firstpredetermined time before resuming the background formatting.

Main control unit 9 checks whether the predetermined time has passed(step S26). If the first predetermine time has not passed, main controlunit 9 returns to step S21 and repeats the process between steps S21 andS23. If the host computer requests for data storage in step S22 and thebackground formatting is not proceeding in step S23, main control unit 9goes to step S25 and stores the data as requested by the host computer.Main control unit 9 checks whether the predetermined time has passed(step S26).

If the first predetermined time has passed, main control unit 9 revisesFDCB 25 (step S27). In response to completing the revision of FDCB 25,main control unit 9 starts measuring time up to a second predeterminedtime before resuming the background formatting. Main control unit 9checks whether the second predetermined time has passed (step S28). Ifthe second predetermined time has not passed, main control unit 9returns to step S21 and repeats the process between steps S21 and S27.If the second predetermined time has passed, main control unit 9 goes tostep S29 and resumes the background formatting. Then, main control unit9 returns to step S21 and repeats the above process. If main controlunit 9 determines that the background formatting has been completed atstep S21, main control unit 9 exits from this process.

The third embodiment is different from the second embodiment in that thetime period between the data storage and the revising of FDCB 25 is notnecessarily equal to the time period between the data storage and theresuming of the background formatting.

Accordingly, in the case wherein multiple requests for data storage aremade in a short period during the background formatting, the opticaldisk drive revises FDCB 25 after all requests for data storage aresatisfied. The optical disk drive can maintain high performance andavoid damaging the FDCB region 25 of the optical disk.

FIG. 6 is a flow chart showing background formatting of the optical diskdrive showed in FIG. 1 according to the fourth embodiment of the presentinvention.

Main control unit 9 starts formatting the disk in the background. Maincontrol unit 9 checks whether the background formatting has beencompleted (step S31). If the background formatting has not beencompleted, main control unit 9 further checks whether the host computerrequests for data storage (step S32). If the host computer requests fordata storage, main control unit 9 interrupts the background. Formatting(step S33). Main control unit 9 stores data in optical disk 11 asrequested by the host computer (step S34). Then, main control unit 9resumes the background formatting (step S35) and returns to step S31.

If the host computer does not request for data storage in step S32, maincontrol unit 9 checks whether the host computer (that is, the user)requests to eject optical disk 11 (step S36). If the host computer doesnot request to eject optical disk 11, main control unit 9 returns tostep S31 and repeats the above process. Main control unit 9 exits thisprocess if it determines that the background formatting has beencompleted in step S31. If the host computer requests to eject opticaldisk 11 in step S36, main control unit 9 interrupts the backgroundformatting and revises FDCB 25 (step S37). Main control unit 9 ejectsoptical disk 11 (step 538) and exits this process.

As described above, in the case wherein the host computer makes multiplesuccessive requests for data storage, main control unit 9 revises FDCB25 after performing all data storage requested by the host computer.Accordingly, the optical disk drive can maintain a high levelperformance and damage the FDCB 25 region of the optical disk less.

If the user wants to take out the optical disk such as DVD+RW while theoptical disk is being formatted in the background, the optical diskdrive needs to interrupt the background formatting. The fifth embodimentof the present invention operates without causing any problem under suchsituation.

FIG. 7 is a flow chart showing background formatting of the optical diskdrive showed in FIG. 1 according to the fifth embodiment of the presentinvention.

Main control unit 9 starts formatting the disk in the background. Maincontrol unit 9 checks whether the background formatting has beencompleted (step S41). If the background formatting has not beencompleted, main control unit 9 further checks whether the host computerrequests for data storage (step S42). If the host computer requests fordata storage, main control unit 9 interrupts the background formatting(step S43). Main control unit 9 stores data in optical disk 11 asrequested by the host computer (step S44). Then, main control unit 9resumes the background formatting (step S45) and returns to step S41.

If the host computer does not request for data storage in step S42, maincontrol unit 9 checks whether the host computer requests to interruptthe background formatting (step S46). If the host computer does notrequest to interrupt the background formatting, main control unit 9returns to step S41 and repeats the above process. Main control unit 9exits from this process if it determines that the background formattinghas been completed in step S41. If main control unit 9 determines thatthe host computer requests to interrupt the background formatting instep S46, main control unit 9 interrupts the background formatting (stepS47). Main control unit 9 revises FDCB 25 (step S48) and exits thisprocess.

As described above, in the case wherein the user requests data storageduring the background formatting, main control unit 9 does not reviseFDCB 25 in response to each data storage request of the user.Accordingly, the optical disk drive can maintain a high levelperformance and damage the FDCB 25 region of the optical disk less. Ifthe user wants to take out the optical disk during the backgroundformatting, the optical disk drive interrupts the background formattingbased on the user's request and ejects the optical disk after revisingFDCB 25.

It is the user that takes out the optical disk during the backgroundformatting or turns off the optical disk drive. Likewise, the user cancause the optical disk drive to revise FDCB 25. In the sixth embodimentof the present invention, the optical disk drive revises FDCB 25 inresponse to the user's request to do so.

FIG. 8 is a flow chart showing the background formatting of the opticaldisk drive showed in FIG. 1 according to the sixth embodiment of thepresent invention.

Main control unit 9 starts formatting the disk in the background. Maincontrol unit 9 checks whether the background formatting has beencompleted (step S51). If the background formatting has not beencompleted, main control unit 9 further checks whether the host computerrequests for data storage (step S52). If the host computer requests fordata storage, main control unit 9 interrupts the background formatting(step S53). Main control unit 9 stores data in optical disk 11 asrequested by the host computer (step S54). Then, main control unit 9resumes the background formatting (step S35) and returns to step S51.

If the host computer does not request for data storage in step S52, maincontrol unit 9 checks whether the host computer requests to revise FDCB25 (step S56). If the host computer does not request to revise FDCB 25,main control unit 9 returns to step S51 and repeats the above process.Main control unit 9 exits this process if it determines that thebackground formatting has been completed in step S51. If main controlunit 9 determines that the host computer requests to revise FDCB 25 instep S56, main control unit 9 interrupts the background formatting (stepS57). Main control unit 9 revises FDCB 25 as requested by the hostcomputer (step S58) and exits the background formatting process.

In this embodiment, the revision of FDCB 25 is performed based on theuser's request. Accordingly, FDCB 25 of the optical disk is revised atthe most appropriate timing based on the user's request. The opticaldisk drive can maintain a high level performance and damage the FDCB 25region of the optical disk less.

As described above, FDCB 25 includes various items of informationtherein, such as information (address) indicating the region that hasbeen formatted in the background and the unformatted region where userdata are recorded. These information items are useful in avoidingstoring dummy data in the unformatted region where the user data havebeen recorded.

Accordingly, it is not necessary to revise FDCB 25 in the case whereinthe user data are stored only in the formatted region during thebackground formatting and the case wherein the optical disk is not beingformatted in the background. Accordingly, the optical disk driveaccording to the seventh embodiment that will be described below revisesFDCB 25 only when the information to be stored in FDCB 25 has changed.

FIG. 9 is a flow chart showing the background formatting of the opticaldisk drive showed in FIG. 1 according to the seventh embodiment of thepresent invention.

Main control unit 9 starts formatting the disk in the background. Maincontrol unit 9 checks whether the background formatting has beencompleted (step S61). If the background formatting has not beencompleted, main control unit 9 further checks whether the host computerrequests for data storage step S62). If the host computer request fordata storage, main control unit 9 interrupts the background formatting(step S63). Main control unit 9 stores data in optical disk 11 asrequested by the host computer (step S64). Main control unit 9 checkswhether the information stored in FDCB 25 needs to be changed.

If the information stored in FDCB 25 does not need to be changed, maincontrol unit 9 resumes the background formatting (step S67). Maincontrol unit 9 returns to step S61 and repeats the above process. If theinformation stored in FDCB 25 needs to be revised, main control unit 9revises FDCB 25 (step S66) before resuming the background formatting instep S67. Main control unit 9 exits this process if it determines thatthe background formatting has been completed in step S61.

As described above, the optical disk drive according to this embodimentrevises FDCB 25 only when the information stored in FDCB 25 needs to berevised. Accordingly, the optical disk drive can maintain a high levelperformance and avoid damaging the FDCB 25 region of the optical diskcaused by frequent revision (rewriting) of FDCB 25 information inresponse to requests for data storage, for example, by the user.

Yet another embodiment of the present invention will be described belowby reference to FIG. 10. An information processing system 61 includes a3.5 inch flexible disk drive 62 and an optical disk drive 63 such as aDVD+RW drive according to an embodiment of the present invention. Theoptical disk drive may be a CD-RW drive that embodies the presentinvention. The optical disk drive 63 is embedded in the informationprocessing system 61, but the optical disk drive 63 may be a so-calledbuilt-in type. The host computer is embedded in the informationprocessing system 61 in this case. Since the information processingsystem 61 includes the data storage apparatus 63 according to anembodiment, a user of the information processing system 61 can obtainthe benefits of the features and advantages of the present invention.

The optical disk drive 63 may be a stand-alone type that is separatefrom and controlled by an external host computer. The Informationprocessing system 61 is not limited to a desk top type personalcomputer, but it may be a notebook type personal computer.

As described above, a data storage apparatus according to an embodimentof the present invention can revise control information indicating theaddress up to which the background formatting has been performed and theaddress of an unformatted recording region in which user data has beenrecorded, for example, at an appropriate timing during the backgroundformatting.

The preferred embodiments of the present invention are described above.The present invention is not limited to these embodiments, but variousvariations and modifications may be made without departing from thescope of the present invention.

This patent application is based on Japanese priority patent applicationNo. 2001-229258 filed on Jul. 30, 2001, the entire contents of which arehereby incorporated by reference.

1-17. (canceled)
 18. A method comprising the steps of: formatting arewritable recording medium in the background; interrupting thebackground formatting when a host computer requests to store data insaid rewritable recording medium; storing said data in said rewritablerecording medium after interrupting the background formatting; revisingcontrol information stored in a predetermined region of said rewritablerecording medium after storing said data; and resuming the backgroundformatting after revising said control information, wherein adetermination is made as to whether a first predetermined time haspassed after storing said data in said rewritable recording medium; andsaid control information is revised after said first predetermined timehas passed.
 19. The method as claimed in claim 18, wherein adetermination is made as to whether a second predetermined time haspassed after revising said control information; and the backgroundformatting is resumed after said second predetermined time has passed.20. A method comprising the steps of: formatting a rewritable recordingmedium in the background; interrupting the background formatting when ahost computer requests to store data in said rewritable recordingmedium; storing said data in said rewritable recording medium afterinterrupting the background formatting; revising control informationstored in a predetermined region of said rewritable recording mediumafter storing said data; and resuming the background formatting afterrevising said control information, wherein the background formatting isinterrupted when a user requests to eject said rewritable recordingmedium during the background formatting; said control information isrevised after interrupting the background formatting; and saidrewritable recording medium is ejected after revising said controlinformation.
 21. A method comprising the steps of: formatting arewritable recording medium in the background; interrupting thebackground formatting when a host computer requests to store data insaid rewritable recording medium; storing said data in said rewritablerecording medium after interrupting the background formatting; revisingcontrol information stored in a predetermined region of said rewritablerecording medium after storing said data; and resuming the backgroundformatting after revising said control information, wherein thebackground formatting is interrupted in response to a request for theinterruption of the background formatting; and said control informationis revised after interrupting the background formatting.
 22. A methodcomprising the steps of: formatting a rewritable recording medium in thebackground; interrupting the background formatting when a host computerrequests to store data in said rewritable recording medium; storing saiddata in said rewritable recording medium after interrupting thebackground formatting; revising control information stored in apredetermined region of said rewritable recording medium after storingsaid data; and resuming the background formatting after revising saidcontrol information, wherein the background formatting is interruptedwhen a user requests to revise said control information; and saidcontrol information stored in said predetermined region of saidrewritable recording medium is revised.
 23. A method comprising thesteps of: formatting a rewritable recording medium in the background;interrupting the background formatting when a host computer requests tostore data in said rewritable recording medium; storing said data insaid rewritable recording medium after interrupting the backgroundformatting; revising control information stored in a predeterminedregion of said rewritable recording medium after storing said data; andresuming the background formatting after revising said controlinformation, wherein said control information stored in saidpredetermined region of said rewritable recording medium is not revisedif said control information has not changed.